{"id":691,"date":"2016-04-27T07:46:34","date_gmt":"2016-04-27T14:46:34","guid":{"rendered":"http:\/\/pro.harman.com\/insights\/?p=691"},"modified":"2016-06-10T08:10:21","modified_gmt":"2016-06-10T15:10:21","slug":"bring-clarity-to-transportation-pa-systems-with-beam-shaping","status":"publish","type":"post","link":"https:\/\/pro.harman.com\/insights\/enterprise\/bring-clarity-to-transportation-pa-systems-with-beam-shaping\/","title":{"rendered":"Bring Clarity to Transportation PA Systems with Beam Shaping"},"content":{"rendered":"

Sprawling, noisy transportation facilities such as airports, bus and train terminals present difficult public address challenges for sound system designers. With long hallways, large echo-ridden rooms and many reflective surfaces, it takes a good understanding of acoustics, sonic energy flow and current technology to deploy an effective and intelligible sound system.<\/p>\n

\"\"The purpose of any public address system is to communicate a message. Speech clarity is especially important in transportation situations where passengers rely on the system to hear arrival and departure notices, paging announcements and emergency and safety information. An email with half the words missing would not be an acceptable form of communication, and you certainly shouldn\u2019t accept a similar effect from a poor public address system.<\/p>\n

The biggest challenge facing sound system designers in this type of application is to devise a system that has a high direct-to-reverberant sound ratio. This means that systems need to focus sound directly to the listeners\u2019 ear, while moving sound energy away from walls, ceilings and other acoustically reflective surfaces. The solution seems straight forward, but in practice, it is very difficult to execute with conventional loudspeakers.<\/p>\n

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Directing sound to listeners’ ears seems straight forward, but in practice is difficult to execute.<\/a><\/div>\n

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To achieve this, sonic beam steering control technology allows speakers like JBL\u2019s Intellivox<\/a> digitally controlled speaker system to focus sonic energy exactly where it is needed\u2014at the listener. Think of the Intellivox\u2019s sonic beam like a spotlight as opposed to a floodlight. Beam steering products have a very narrow vertical coverage angle and a very wide horizontal coverage angle. A process involving precise manipulation of the output level and phase relationship between adjacent components of the overall loudspeaker can easily be controlled via software, allowing the sound designer to adjust the vertical directivity and focus. This allows these vertical column speakers to be mounted parallel to the wall, but still aim sound directly at the listeners\u2019 ear level and away from walls, floors and other surfaces.<\/p>\n

\"\"Traditional beam steering products have limitations, however. A balance has to found between how narrow the sonic beam is, how high the speaker is physically mounted and how much of the audience can therefore be kept within the coverage area. As the height of the speaker is raised and the steering angle increased, the vertical coverage will also have to be increased in order to cover the same audience area. The larger the vertical coverage becomes, the more sonic energy will come in contact with reflective surfaces in the room and the overall direct-to-reverberant field will decrease.<\/p>\n

“Beam Shaping” technology, pioneered by JBL, combats this issue by allowing the sound designer to create a complex asymmetrical vertical sonic beam. By altering the shape of the sound dispersion, the vertically-mounted speakers can better cover all listeners with direct sound (see the image to the right). With this leading technology\u2014developed by the same team who first brought beam steering to market over 20 years ago\u2014much finer, more precise control is possible. Now a speaker can be programmed to evenly cover the nearfield audience while maintaining consistent SPL and frequency response out to the furthest listener.<\/p>\n

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“Beam shaping” evenly covers the nearfield audience while maintaining SPL to the furthest listener.<\/a><\/div>\n

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Related technology is employed in HARMAN’s AXYS Tunnel solution. Here is a video with real-world examples of how the technology improves intelligibility in even the most challenging of installations:<\/p>\n